paitr
paitṛ — in relation with the father; SB 1.19.35
paitṛ-svasreyān — the sons of His father's sister; SB 10.49.9
paitṛ — of Your father; SB 10.70.40
paitṛ-ṣvasreyasya — to Your father's sister's son; SB 10.71.2